Accelerator for the vulcanization of rubber



Patented July 5, 1927.

UNITED STATES PATENT OFFICE;

GEORGE STAFFORD WHITBY, OF MONTREAL, QUEBEC, CANADA, ASSIGNOR TO THE ROESSLER & HASSLAGHER CHEMICAL 00., OF NEW YORK, N. Y., A CORPORATION OF new YORK.

AocnLEnA'ron FOR/THE vuLoANIzArIoN or RUBBER.

1T0 Drawing.

The object of this invention is to provide anew and improved class of accelerators for the vulcanization of rubber which will give to the finished rubber product excellent 5 physical propertiessuch as desirable stress strain relationship, high tensile strength, rapidity of vulcanization at lower tempera-I of matter embodying a thiuram polysulphide of this type and in a second application, S N. 84,154, I have-claimed its use as an accelerator. This present invention relates to another class of compounds of polysulphide nature containing five or more sulphur atoms permolecule.

r This invention relates to the use of compounds which are formed by the reaction of salts of xanthic acids with sulphur chlorides and more particularly to the products formed by treating the salts of Xanthic acids with sulphur monochloride or sulphur dichloride. Specifically my invention deals Application filed January 27, 1926. Serial No. 84,152.

with the productformed by sulphur chlorides with saltsof the oxygen esters of Xanthic acidof the general formula wherein R is any alkyl' group and is a metallic radical or equivalent group such as sodium, potassium, ammonium, etci Throughout the specification and claims I I refer to specific sulphur chlorides as sulphur monochloride and sulphur dichloride giving these the formulas of S 01 and SCI respectively. However, I do not wish to be limited in this since there has been considerable discussion as to the structures. Furthermore sulphiir is very soluble in these sulphur chlorides and at times appears to be present in molecules of a polysulphide nature, having several loosely bound sulphur atoms in addition to those ascribed by the formula. I

' therefore prefer to express the sulphur chlorides above referred to as S CI A If potassium ethyl xanthate, for example, be treated with a sulphur chloride, as S Cl a reaction takes place between two molecules of the xanthate and one molecule of the ch'lo- .ride in a reaction believed to be as follows:

So also a reaction takes place with SCI to give a trisulphide. I have now found that 7 these reactions take place with salts of a 60 great number of xanthates. I have preparedsuch compounds from potassium-ethyl xanthate, potassium-n-propyl xanthate, p0:

tassium-n-butyl izanthate, potassium isoamyl xanthate, potassium i'so-butyl xanthate and potassium allyl xanthate. These prodnets and reactions I believe to be represented by the following general equations:

wherein R is an alkyl radical. Thus if .A. (hrrbethomy sham tetrasulphide. 7.0 grams potassium ethyl xantliate were 1- 7 S C1, is used the productwill be f 1 dissolved. in 120 cc/water. 27 grams sul- I v phur monochloride (8,015) were addedto this drop by cooled with ice and well" agitated. A yellow oil was formed. The oilwasextracted with ether; the ether solution was driedwith calcium chloride and then the ether wasdistilled oft. A yield of about/90% of theoretical was obtained.

and SCI ill i drop while the mixture was 75 i a-(l3-O,-R or (R--OE);S

These compounds are carbalkoxy thione polysulphides. The preparation of these materials is illustrated by the following: 9

solved in a s a small amount of alcohol. This otassium B. Umbalkomy (n-butyl) The above ingredients were mixed on the 271270120 tetrasulphz'de. rubber mill and the compound cured for 60 minutes at the temperature of 10'pound. steam; elongation 9; load at 600% elqng. T90

lbs/inf: tensile 3119 lbs/inf.

It will be noted that the above example illustrates an application of my invention wherein no free sulphur is compounded with the rubber mix as is usual in the art; the

salt was dissolved in water an chilled; poly-sulphide aceeleratorcontams the requl- 7.)

site sul hur for vulcanization. 39.5-grams sulphur monochlorlde (S Cl p 56 grams potassium hydroxide were dis ight excess of n-butyl alcohol; the solution was cooled and 7 6 grams carbon bisulphide added while cooling and stirring. The potassium n-butyl xanthate which precipitated was filtered out and washed with were added with stirring. A light yellow EXAMPLE oil se arated out. This was decantedydIS- Oarbal/cowy (iso-propyl.) tkionc tetraaulsolve in acetone and filtered, and dried for pkide. 80

a. short time with calcium chloride. 69

6 'rams of the above com ound'wertr grams of dry Oll were obtained. p

I mixed with 4.35 grams ethylanili ne; crystals Garballcory (n-btlfyl) thz'mze trisuZph-ide'. separated Ovemlght, i mlxture was used as the accelerator, 1n the rubber formula grams of potassium y Xanthate of Example I, using 2.15 parts by weight of were dissolved water and co le 22 accelerator and cured at the temperature of grams sulphur dichloride were stirred into 10 pound Stemm I the solution; a heavy oil settled out. This oil was dissolved in ether and the solution Timeofcum stretch Loadxatwwy Tensile;

,5 dried w th calclum chloride. The ether was removed by distillation; 56 grams of a clear 1 li SOminutes. 8.2 2400 ha. n. I 4812 lbs. in. 3 ml T obtamed; 45 minutes. 8.0. mlbslinfi 4707lbs.lin.'

rubber 1111K. especially when an amine of the a aniline type is also present. greatly acoeler- EXAMPLE IV.

ate the vulcanization of rubber. increase the [,6 U6 Z I I tensile strength of the rubber and impart my (z'gopmpy t none has? ot-her desirable qualities. I have found it parts b weioht smoked sheet, 5 parts possible to use these accelerators in rubber b i ht ifi' O id 5 arts by weight 1 3 mixes without added free sulphur and still 'h r, 1.25 parts by weight of above com- 10 Obmm satlsfactm'y pound, 1 part by weight ethyl aniline. examples 9 vulcamzed.rubber {made The above ingredients were mixed oil the with these materials the following are given: bb n and cured at the temperature of EXAMPLE I 10 pound steam.

aarzlaikowy- (77f?) tin-one tetrmzphide' Time of cure. Stretch. g g i Tensile. 6 grams of the above compound were. i mixed with 6.52 rams dibenzyl amine; heat, n m, 8.6 1025 lbs/1:11.; moms m1 e yellow crystals separated ease; as assets ease/a out. Th s mlxture was used as the aecelerar v tor 1n the formula: EXAKHJE 100 parts by weight smoked sheet 5 parts I bv weight zinc oxide, 5 parts by welght sul- Uarballrozvg (iso-propyl) thz'one tm'sulphide. phur, 1.3 parts by weight accelerator. After v Formula an ixin s milling,- the rubber mixture was cured at the 77 d m a m but temperature of 10 pound steam and the folparts by welght of amlme Instead I v 0 ar et 'lowmg results obtained: fi p l amhne sametempeliature of Load at 1 55 Time of s along. 0 Tensile Time Menu. Stretch. M ggy Tensile. I

4 i 1.351133%. 3.3 llttlfilli: fight/5;; g a yg-g ggg -y -g ggggg -t q l a l xmnues. 5.1. .1. mmum 8 45 minutes. a. 4 1300 lbs/i3. 4112 lei i3:

GOminutee. as ISOOIbs/in. 375s lbs/i111? EXAMPLE II. v j

Oarbetkowy thioaw tetmsulphz'cie. Ex

100 parts by weight smoked sheet, 5 arts laarbazkowy (isonamyz) thiom ire-sulphide r by weight zinc oxide, 5 parts by weig t; of. l0 grams of the above compounds were fabove compound, 2.5 parts by weight aniline, mixed with 5.4 grams aniline. Heat was evolved and crystals formed. 7 2.09 parts of this mixture were used as the accelerator in the rubber formula of Example I. Cured I at temperature of 10 pound steam.

Time of cure. Stretch. g g i Tensile.

50 minutes. a. 7 2050lbs.lin. 5330 lbs in. SOmmutes. 8.5 2300lbs./in. 465 11bs./in.

\ EXAMPLE VII. Oai'baUcOwy (re-bitty!) thz'one trisulphide.

accelerator in the 6 gram's of this compound were mixed with 7.15 grams clibenzylaminej heat, was

r evolved and crystals separated. .1.37. parts by weight of this mixture was used as the rubber formula of-Example I.

Time ofcure. Stretch. gg i Tensile.

40 minutes. 9.5 750lbs./in. .3312. usljin. minutes. 8.4 1675 lbs/in. 4402 lbs/in. minutes. 8.7 1600 lbs/1n. 4815 lbs/in.

. EXAMPLE VIII. Oarbalkbmy (iso-amg l) thione tetrasulphide. 1.25 parts of the above were used as the accelerator in the rubber compound of Example I and the mixture cured at thetemperatureof 10 pound steam.

Time olcure. Stretch. v Tensile.

so minutes. 9.61 moms m: 2624lbs/in.

minutes. 8.82 600lbs.1in. 2419 lbs/in! EXAMPLE IX.'

C'arbalZaOaiy (n-propyl) tMbM tetrasalpkz'de.

0.625 parts of theabove and 0.825 parts of dibenzylamine were incorporated as the accelerator in the rubber formula of Example I and the compound cured at the temperature of 10 pound steam.

Time of cure. 4 Stretch. g gg m Tensile.

40 minutes. 9. a 12061bs.lin.' 4044 lbs/in. 50 minutes. 8. 9 1800 lbSJllL 5417 lbS./i11. 60 minutes. 8. 8? 18m lbs/in. 4805 lbs/in.

lrVhile I have given above specific examples of methods of preparing my accelerators and specific uses thereof inrubber mixtures I do not wishto be limited to the methods of manufacture given nor the methods of use given since my accelerators are applicable in many variationsand may be pre-, pared in any suitable .way.

What I claim is: I

1. A process of treating rubber or similar material which comprises incorporating with the rubber compound a vulcanizing agent,-

an amine, carbalkoxy thione polysulphide containing 5 or more sulphur atoms per molecule, and vulcamzmg the rubber.

and vulcanizing. the rubber.

4:. A process of treating rubber or similar material which comprises amine, and an organic compound comprismg the-group wherein R is an organic radical, and. vulcanizing the rubber.

5. A process of treating rubber or similar material which comprises incorporating with the rubber a vulcanizing agent, an

amine,'and an organic compound compriswherein R is an alkyl radical, and vulcanizing the rubber. '6. A process of treating rubber or similar material which comprises incorporating with the rubber a vulcanizing agent,-an aromatic amine, and an organic compound comprising the group --o-s,-o-,

and'vulcanizing the rubber.

7. A process of treating rubber or similar material which comprises incorporating with the rubber a vulcanizing agent, an

amine, and the reaction product of a xanthate with a sulphur chloride of theformula- S;Cl,, and vulcanizing the rubber.

8. A ,rocess of treating rubber or similar materia which comprises incorporating with the rubber a vulcanizing agent, an arcmatic'amine of the aniline type, and the re: action product of a xantha-te with a sulphur chloride of the formula S GI and vulcanizing the rubber.

9. A process of treating rubber or similar material which comprises incorporating with the rubber a vulcanizing agent, an aroincorporating -w'ith the'rubber a vulcanizing agent, an

matic amine,.and the reaction product of the potassium salt of an alkylxanthic acid with material sulphur monochloride, and vulcanizing the rubber. a, p

10. A process of treating rubber or similar material -which comprises incorporating with the rubber a vulcanizing agent, an aromaticamine, and the reaction product of potassium butyl Xanthate with a sulphur chloride of the formula 5 01 and vulcanizing the rubber.

11. A process of treating rubber or similar which comprises incorporating with the. rubber a vulcanizing agent, an

aromatic amine, and thereaction product of potassium butyl Xanthate with sulphur monochloride, and vulcanizing the rubber. 12. The process ofaccelerating the vulcanization of rubber, comprising vulcanizing the same 1n the presence of a carbalkoxy thione polysulphide containing 5 orf more sulphur atoms per molecule.

13. The process of accelerating the vulcanization of rubber comprising vulcanizing the same in the presence of an organic compound comprising the group.

14, The process of acceleratingthe vulcanization of rubber comprising vulcanizing the same in the presence of an organic com-- pound comprising the group (wherein R is an alkyl radical). 16. The process of accelerating tl1 e-vul canization of rubber comprising vulcanizing the same in the presence of an organic compound comprising the group --C-Br-C.

17. The process of accelerating thevuL canizatibn of rubber comprising vulcanizing the same in the presence of the reaction T product of a xanthate with a sulphur chloride of the-formula S Cl 18. The process of accelerating the ub c'anization of rubber comprising vulcanizing the same in the presence of the reaction product of a salt of an alkyl xanthic acid with sulphur monochloride.

19. The process of accelerating thevuls' canization of rubber comprising vulcanizlng the same in the resence of the'reactlon product of potassium butyl xanthate with sulphurmonochloride.

20. A vulcanized rubber a vulcanizing agent and a reaction product of a xanthate with a sulphur chloride of the formula S CI 21. A Vulcanized rubber derived from rubberor similar material incorporated with a vulcanizing agent an amine, and a reaction product of an alkyl xanthate with a sulphur chloride of the formula S161,

22. A milcanizecl rubber derived from rubber or similar material with which has been incorporated anamine and a reaction product of potassium butyl xanthate with sulphur monochloride.

23. The method of vulcanlzing riibber without the additionof sulfur, which comprises subjecting the rubber to vulcanization with an organic golysulfide of the general formula (CS) x (where :v' is a number greater than 2) as the vulcanizing agent.

Signed at Perth Amboy in the county of derived from' rubber or similar material incorporated with i Middlesex and State of New Jersey this 16th day of January, A. Dl 1926. I GEORGE STAFFORDWHITBY. 

